where \(\mathfrak {r}\)  is the solvable radical of \(\mathfrak {g}\) , \(\mathfrak {r}_\infty \)  is the intersection of its lower central series, \(\mathfrak {s}\)  is a Levi complement and \((\mathfrak {s},\mathfrak {r})\)  is the Lie subalgebra generated by \([\mathfrak {s},\mathfrak {r}]\) ; see [1]} and [2]}.
